Sign and support apparatus

ABSTRACT

The sign has an aerodynamic cross-sectional shape, is supported along a center of gravity line and is normally prevented from rotating by a releasable support member that is coupled to the main sign support structure. The sign may be supported either horizontally or vertically along a hingeline that passes through the sign. Both the sign and support are fabricated with a lightweight core material surrounded by a stronger, relatively thin skin material. An optimum strength support is obtained by providing a circular cross-section in a plane that passes through the normal (perpendicular) force center on the sign and the support for each incremental section of the support.

United States Patent [191 I [111 3,828,455

Bentley [4 Aug. 13, 1974 [54] SIGN AND SUPPORT APPARATUS 3,521,390 7/1970 Carlson 40/ 125 H [76] Inve tor: Ra p L- t ey, 79 co R 3,526,050 9/1970 Weller 40/145 R Andover Mass Primary Examiner-Robert W. Michell [22] Filed: Jan. 17, 1973 Assistant Examiner-John F. Pitrelli 21 A LN .;324,349 1 pp 0 57 ABSTRACT Related US. Application Data The sign has an aerodynamic cross-sectional shape, is

[63] Continuation of Ser. No. 99,000, Dec. 17, 1970, Supported along a center of gravity e and is nob abandoned mally prevented from rotating by a releasable support member that is coupled to the main sign support struci" /125 g ture The sig may be supported either horizontally or [58] F111 01525131;IIIIIIIIII'Zb/iiifiH, N, vhhhhhhy hhhg h hhgehhh hhhh hhhhhh hhhhhgh hhh sign. Both the sign and support are fabricated with a light-weight core material surrounded by a stronger, relatively thin skin material. An optimum strength [56] References Cited support is obtained by providing a circular cross- UNITED STATES PATENTS section in a plane that passes through the normal (per- 782,811 2/1905 Ames 40/145 R pendicular) force center on the sign and the support 1,982,960 12/1934 'Link 40/212 for each incremental section of the support 2,925,893 2/1960 Baas 52/723 X 3,287,840 11/1966 Keats 40/125 H x 18 Claims, 17 Drawing Figures PAIENTEB RE I 31974 SHEET 1 0f 4 INVENTOR.

BY 9*o'eg Wdh gem 92b PAIENI ms: slim SHEU 3 BF 4 D D D m WN 6T w s m K W E/ H ilk LAII e PAIENTEB NIB! 3. 828.455

sumuum l F/G 9A C x r Q i V f i 5 F HIGHWAY SIGN C b 2 B 9 i i f l FF/G/OB INVENTOR E E afigiwmm SIGN AND SUPPORT APPARATUS This is a (continuation, of application Ser. No. 99,000, filed Dec. 17, 1970, now abandoned.

SUBJECT MATTER AND BACKGROUND OF THE INVENTION The present invention relates, in general, to sign and sign support apparatus and, in particular, is concerned with a sign and sign support that is characterized by a relatively large strength-to-weight ratio and is preferably for use along a road or highway.

Existing signs, particularly those used along roadways, are generally constructed of flat plates which are reinforced with a frame or ribs to withstand wind forces. The signs are, in turn, supported in a fixed position by rigid supports. The supports are usually constructed from channel beams, I-beams or tubular pipes. These supports provide for fixed sign positioning by being rigidly reinforced into the ground or a similarly immovable object. Some of the disadvantages associated with existing sign and support members are: (1)

they are heavy and bulky; (2) they are difficult to 'fabri-' cate and assemble; and (3) when located along a highway they may cause substantial injury to passengers and damage to an impacting vehicle.

SUMMARY OF THE INVENTION It is an important object of the present invention to provide an improved sign and support apparatus.

It is another object of the invention to provide a sign and sign support that is characterized by a relatively large strength-to-weight ratio.

Another object of the invention is to provide a safe sign and sign support for use along a roadway.

It is a further object of the invention to provide an aerodynamically-shaped sign that is normally restrained in a readable position and is released under high wind condition.

It is still a further object of the invention to provide a sign that can be restrained in more than one fixed readable position, thereby being capable of displaying different sign nomenclatures. I

A further object of the invention is to provide a sign support structure that is relatively light in weight and has an optimized cross sectional configuration that provides for maximum strength.

Another object of the invention is to provide a sign support structure that is circular in a cross-section that passes through the force center of the sign and the support for each incremental section of the support.

Another object of the invention is to provide a support structure that shatters when hit by a vehicle thereby minimizing vehicle impact.

Still another object of the invention is to provide a sign and sign support apparatus that can be fabricated in many different configurations.

According to the invention, the sign is relatively light-weight, has an aerodynamic cross-sectional shape and is hingedly rotatable about a member which passes through the sign. The sign is normally prevented from rotating by a releasable restraining member. The restraining member holds a sign in a readable position under normal wind forces. When the wind exceeds a given pre-determined force value the sign is released by the restraining member and rotatably assumes a minimum force (drag) position. The support structure for the sign has an optimized strength-to-weight ratio. The

cross-section through the support is circularin aplane that passes through the normal (perpendicular) force .center on' the sign and the support, for each incremen- BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a horizontally supported sign and sign support in accordance with the principles of this invention, partially cut away.

FIG. 2 shows a. vertically supported sign according to the invention, partially cut away.

FIG. 3 is a cross-sectional view through the sign shown in FIG. 1 along line 33.

FIG. 4 is a diagrammatic representation for a horizontal support, according to the invention, indicating pertinent dimensional and analytic parameters.

FIG. '5 is a diagrammatic representation of a vertical support, according to the invention, indicating pertinent dimensional and analytic parameters.

FIGS. 6A, and 6B, and 6C are diagrammatic representations showing the vertical component of the horizontal support of FIG. 4 in front, side and crosssectional top views and associated parameters.

FIG. 7 is a perspective representation showing the horizontal component of the horizontal support of FIG. 4 and associated parameters.

FIGS. 8A, 8B and 8C are diagrammatic representations, showing the horizontal segment of the horizontal component of FIG. 7 in front, top, and 'cross-sectional side views and associated parameters.

FIGS. 9A- and 9B are diagrammatic representations showing the transitional segment of the horizontal component of FIG. 7 in side and top views and associated parameters.

FIGS. 10A and 10B and 10C are diagrammatic representations showing the vertical support of FIG. 5 in front, side and cross-sectional top views and associated parameters.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIGS. 1 and 2 show two separate embodiments for the sign and sign support apparatus. FIG. 1 shows a horizontally hinged sign 10 supported by member 20. FIG. 2 shows a vertically hinged sign 30 supported by member 40. Members 20 and 40 may both be rigidly supported within the grounds or a similarly immovable object. The sign and the support members include a light weight inner core material, such as a foamed plastic, covered by a relatively thin skin material of higher strength such as fiberglass, and are constructed to have a relatively large strength-to-weight ratio. The support structure is discussed in more detail in association with FIGS. 4 through 10.

SIGN

FIG. 1 shows a perspective view of the sign 10 having width W and height H, and sign support member 20. The member 20 may be constructed in accordance with the principles of the invention or other support members including conventional ones may be used with Sign 10.

FIG. 3 is a cross-sectional view through the sign of FIG. 1 taken along line 3-3. The cross-section is in the shape of an aerodynamic air foil. The sign includes a light-weight core material 27, such as a foamed r cellular plastic, surrounded by a thin skin 25 of fiberglas, for example. The sign is supported so that the center of gravity of the cross-sectional air foil coincides with the center line of internal portion of support 20. In FIG. 1 this center of gravity line passes through the sign on -quarter of the way down from the top edge, as shown. The internal portion of the sign 10 includes a torque tube 17 for facilitating the easy rotation of sign 10 about support 15. Tube 17 is provided, as shown, touching skin 25 on its inner surface, in order to transmit stresses from the sign surface loads to the support.

The wind forces upon the sign 10 may be resolved into a normal force F applied at a sign force center which for the embodiment of FIG. 1 is at approximately the mid-point of sign 10. Sign 10 is able to rotate about portion 15 of member except when restrained by restraining members 11.

The sign and support shown in FIG. 1 may be provided with two restraining member 11, only one of which is clearly illustrated in FIG. 1. Restraining member 11 includes a cylindrical arm 13 which forms a part of sign 10 and extends outwardly from sign 10 about member 20. Each arm 13 has a pair of oppositely positioned holes for accommodating a shear pin 12, or the like. Member 20 would also be provided with a hole that would align with the holes in the arm 13 to allow pin 12 to insert therethrough and hold sign 10 in a normally restrained position relative to support member 20. A second restraining member including a shear pin could also be provided on the left side of sign 10, as viewed in FIG. 1.

When the wind increases to a value where the force F exceeds a predetermined value, the load upon the pins 12 will cause them to sheer and the sign will rotate to a streamlined position as indicated in FIG. 3. In this position the drag upon the sign and the support is reduced to a minimum. In order to restrain the sign to a fixed position again pin 12 is replaced. This operation is significantly less time consuming and less costly than having to replace the entire structure destroyed by an excess wind force.

In addition, if the particular sign is located adjacent to a roadway and a vehicle hits the sign it will yield more than a rigid sign and will cause less damage to the impacting motor vehicle.

A further advantage of the present invention is realized by referring to FIG. 2 where a vertically hinged sign is shown. With the arrangement of FIG. 2 the sign 30 may be restrained in one of two readable positions. Sign 30 has an aerodynamic shape and includes a sleeve 34 which may be circular in cross-section. Sign 30 rotates about internal support portion 32 which is usually integrally formed with the remaining exposed portion of support 40, except when secured by restraining members 31.

As in FIG. 1, the sign and support shown in FIG. 2 may be provided with two restraining members 31 similar to those shown in FIG. 1. Restraining member 31 includes a cylindrical arm 33 which forms an integral part of sign 30 and extends outwardly from sign 30 about support member 40. Each arm 33 has a pair of oppositely positioned holesfor accommodating a shear pin 35. Member 40 also is provided with a hole that aligns with the holes in the arm 33 to thereby allow pin 35 to insert through both the member 40 and arm 33, and hold the sign 30 in a normally restrained position relative to support member 40.

When it is desired to restrain the sign in a new position the pins 35 may be extracted or screwed out in the event screw threads are used. The sign may then be rotated to a second position and new shear pins inserted to restrain it in that position. In either position, however, when an excessive wind force occurs the pins 35 shear and the sign 30 assumes a minimum force position, as previously discussed with reference to FIGS. 1 and 3.

With the arrangement of FIG. 2 the sign can have different legends written on both sides. One side of the sign, for example, could be provided with standard roadside nomenclature, while the other side could display emergency or military symbols.

SUPPORT STRUCTURE FIGS. 4 and 5 show two separate embodiments of the sign support structure. The support structure is similar in construction to the sign and includes a lightweight core material such as a cellular or foamed plastic surrounded by a stronger, thin-walled jacket such as fiberglass. The support for the horizontally hinged sign of FIG. 2, is shown in FIG. 4 along with associated support parameters. The wind forces on the sign can be resolved into a force F normal to the sign at the midpoint thereof.

The support system may be divided into two components. The vertical component extends from Section A-A to Section BB. Section BB lies in a horizontal plane with respect to gravity with the vector defining force F, and is the fundamental section to which all other support sections are related. The horizontal component extends from section 13-8 to section D-D.

The stress imposed by the force F upon any section of the support can be resolved into a torque T, and reaction load R,,. The reaction load, R is equal to the normal wind force F at all support sections. The torque T, is equal to the product of force F and distance D, which is a function of the angle 0. The angle 0 is, in turn, determined in part by the sign size W, and H support overhang, P, and support height H. The limiting angles of 6 as shown in FIG. 4 are 0,, and 6 These angles may be determined as follows:

6,, Arctan (H H,/4)/(W /2 P), and

9,, Arctan (I-I,/4)/(W,/2).

It has been found that the optimum strength for a sign of the type described requires a support with a crosssection that is circular in a plane that passes through the force F and any point along the centerline of the support. Since force F is perpendicular to the plane containing the centerline of the support, any plane through force center F is also perpendicular to the plane containing the centerline of the support, any plane through force center F is also perpendicular to the plane containing the centerline of the support. The only circular cross-section thus defined which also lies in a horizontal plane is section BB. All other crosssections thus defined as circular in a plane that passes 5 through the force F are elliptical in any'other plane perpendicular to the plane containing the centerline of the support. (For convenience reference will be made herein to horizontal planes or cross-sections intending to specific aforesaid perpendicular or vertical planes or cross-sections. Further force center of F means the point of the force vector P on the sign at which all perpendicular forces may be resolved into a single component). The dimensions of the elliptical cross-section are de ermined by the horizontal projection of an inclined circle whose major axis equals the circle radius and minor axis is a cosine function of the angle 6. In FIG. 4, the sections AA and D--'D are both elliptical in shape when horizontally projected and vertically projected, respectively.

The change in the torque T due to the change in the torque arm D, can be compensated for by either a direct proportional change in the thickness, t, of the stressed skin of the support or a change in the radius of the coplanar, circular cross-section, which varies as the square root of the changing torque arm (D The coplanar radius is the radius measured at right angles to the vertical plane of the sign and support.

A vertically hinged sign is shown in FIG. 5 along with associated support parameters. The normal force on the sign can be resolved into a force F normal to the sign at the midpoint thereof. The structural concept of the vertical support is similar to that of the horizontal support. The reference section GG of the support is in a horizontal plane that passes through the force point F, is circular, and is contained within the sign 30. N exposed portion of the support is circular in a horizontal cross-section. All cross-sections on an axis other than that through section GG are circular in a plane that passes through the force point of F and are elliptical in a horizontal cross-section. Cross-section E--E and F-F are both elliptical in FIG. in horizontal planes.

For a better understanding of the concepts of the invention specific examples are considered below. In these examples both variations in skin thickness and coplanar radius are considered.

HORIZONTAL SUPPORT Verticle Component Referring to FIG. 4, there is shown the horizontal support member and associated dimensional parameters. The configuration of the vertical component 22 between sections A-A and BB is based upon the initially chosen dimensions of section BB; the torque T skin thickness t and cross-sectional radius r,,. Throughout this specification the subscripts a,b,c and d refer to their respective cross-sections A-A, BB, CC and DD while subscript x refers to other crosssections. FIGS. 6A, 6B and 6C show front, side and top cross-sectional views of the vertical component 22 for a constant skin thickness configuration. A vertically hinged support is considered hereafter constructed according to the invention and using a constant coplanar radius.

Assuming a vertical, straight support center line for component 22 the torque load T for any section X-X is a function of the angle 0 to the particular section from the force center:

T, T sec 0 The secant (sec 6) varies from a value of 1 at zero degrees (section BB) to values greater than 1 for larger angles. From the above equation it can be seen that the torque does increase as 0 increases and as the torque arm D, increases.

As previously stated, the change in torque with changes in torque arm between section AA and BB can be compensated for by varying the coplanar radius, r,, of the particular cross-section. If the skin thickness remains constant, then the equations fort, and r, at any section X-X are:

t, t constant, and

Because the radius varies as the square root of the torque, equation (4) shows both the 0 and square root relationships.

If, in the alternative, the coplanar radius r remains constant then the equations for r, and t, are:

r, r constant, and

t, t sec 0,

since the skin thickness varies as a direct function of the torque.

By varying both skin thickness and circular coplanar radius for different segments or components of the support, it is apparent that an unlimited number of support combinations exists.

Up to now only coplanar (with F) dimensions have been considered. The horizontal projected crosssections are now considered. The horizontal or perpendicular to the centerline cross sections are elliptical, except for section BB. If the skin thickness remains constant then I, t,,. The elliptical cross-section, however, is defined by major and minor axis dimensions, b, and a,, respectively. The elliptical cross-section axis, 12,, is perpendicular to the plane of the sign and support and equals the radius of the circular cross-section, r which is an angular function of the basic radius r,,, so that:

sec 6 The elliptical cross-sectional minor axis, a in the plane of the sign and support is an angular function of the circular coplanar radius r, which is, in turn, an angular function of the basic radius r,,, so that:

a, r cos 0 For the case where the skin thickness varies and the coplanar radius, r remains constant, or r, r,,, then the equations for (1,, b and I for any section XX are:

a =r cos 0=r cos 0,

b, r,. r and t t sec Referring to FIGS. 6A, 6B and 6C there are shown three views of the vertical component of the support between sections AA and B-B, for the constant skin thickness application. The top cross-sectional view taken at section XX is elliptical and has a major axis b,, and a minor axis a,,. The major axis b, is slightly greater than the basic radius r whereas the minor axis a is slightly less. The reasons for the configuration of FIG. 6C will become apparent after considering equations (6) and (7) above. The axis b, increases because the sec 0 is greater than one and its square root is also. The axis a,, however decreases because the cos 0 is less than one as is its square root. The front and side views show the tapered configurations.

HORIZONTAL COMPONENT HORIZONTAL SEGMENT Horizontal segment 26 can be analyzed in a similar manner to vertical segment 22 by referring to FIGS. 8A, 8B and 8C. All vertical cross-sections between and including sections CC and DD are elliptical. The torque load T with relation to section B-B is a function of the angle 0 and certain sign/support parameters trigonometrically arrived at:

T T K sec 0 I shere K is less than 1, W equals the sign width, X equals the distance from the edge of the sign to the section XX, (the distance x obviously varies with the position of section XX and thus both K and 0 are functions of x), P equals the distance from the edge of the sign to the section BB and K (W, 2 (W +2P). It is noted that equation l 1) above is similar to equation (3) for the vertical component except for the factor K which is less than one because X is always less than P.

For constant skin thickness applications t, t. The elliptical, vertical cross-section may again be defined by major and minor axis dimensions, b, and a respectively. The elliptical cross-section axis b is perpendicular to the plane of the sign and support and equals the radius of the circular cross-section r which is an angular function of the basic radius n, and certain dimensional parameters:

b =r,=r,,Ksec 0 (12) It is noted that equation (12) is similar to equation (6) for the vertical component except for K.

The elliptical cross-section minor axis a,,, in the plane of the sign and support is an angular function of the circular complanar radius r,,:

a =r sin 0 a =r K sec Osin 0 (1 Equation I3) is similar to equation (7) for the vertical component except for K and a different trigonometers relationship.

For the case where the skin thickness varies and the coplanar radius r remains constant, or r, r,,, then the equations for a b, and t, for any section XX are:

Referring to FIG. 8C in particular the horizontal segment 26 is constructed with a constant skin thickness which is elliptical and has a major axis b, and minor axis a The major axis b, is slightly less than the basic radius n, whereas the minor axis a is less than axis b These dimensions are smaller than for the vertical component 2 2, in part, due to the shorter average torque arm for the horizontal segment 26. The reasons for the configuration of FIG. 8C should become apparent after considering equations (12) and (13) above. From equation (12) the axis b varies as a function of sec 6 and K. K is controlling to cause 1),, to be smaller than r Equation (l3) indicated that a I which also varies as the sin 0 is even smaller than b because the sin 0 is always less than one.

TRANSITIONAL SEGMENT Transitional segment 24 can be analyzed by referring to FIGS. 9A and 9B, which also show associated dimensional parameters. In view 9A, the center line for the transitional segment 24 has been selected illustratively as a quarter of an ellipse, between sections B-B and CC. Section X-X is normal to the center line of the segment and varies between a horizontal and vertical cross-section between sections B-B and CC respectively.

From the dimensions in FIGS. 9A and 93 it is possible to define the trigonometric relationships for the angles 0 and B. The angle 0 is an angle measured from the horizontal to a plane that passes through the normal force F and a point on the center line of the support at the particular section XX. The angle B is an angle measured from the horizontal to a plane that is tangent to the elliptically shaped center line at section XX. The torque load T with relation to section BB is a function of the angle 0 and certain sign/support parameters trigonometrically arrived at:

where K (W,/2 Q n) (W,/2 P) and is equal to or less than one, W, equals sign width, 0 equals the distance from the edge of the sign to section CC, n equals the distance from section CC to section XX, and P equals the distance from the edge of the sign to section 8-8. The distances m and n shown in FIG. 9 vary as the position of section XX changes and thus both K, 0 and B are functions of m and n.

VK, sec 6 b r, r

The value of K is the same as that calculated for equation (17).

The elliptical cross-sectional minor axis a in the plane of the sign and support is an angular function of the circular coplanar radius r,,:

a =r sin (9+B) a,=r,, -1( sec 6 sin B) For the case where the skin thickness varies and the coplanar radius r remains constant, or r,. r,,, then the equations for a,, b, and t, for any section X-X are:

a r sin (0 +B) =r sin (0 B) b r, r,,, and

t, t sec 9 Referring to FIGS. 9A, and 9B the transitional segment 24 is constructed with a constant skin thickness. From the top view of FIG. 9 it is seen that the major axis b varies from a value of r at section BB to a slightly smaller value at section C-C. The minor axis varies from a value of r,, at section BB to a smaller value than b at section C--C. Equations (18) and (19) indicate these relationships. In these equations K is less than one because Q n is less than P. (See equation (17)). In equation (18) b, is less than n, because K is less than one. In equation (19) a, is less than I), and r because K is less than one and sin (9+ B) is also less than one.

EXAMPLE HORIZONTAL SEGMENT Referring to FIG. 4 and Table 1 below, variations in a,,, b and t are shown, calculated for varying skin thickness t, and varying coplanar radius b, respectively. The values shown are non-dimensional and relate to section BB as the basic cross-section.

TABLE I The values in Table I were arrived at by using the following dimensions: I-I, equal to 10 feet; W, equal to 20 .feet; H equal to 27.5 feet; P equal to feet; and Q equal to 10 feet. The sections were taken at five footintervals (stations).

The basic size of section BB, to which all other sections are sized, is based on the load imposed by an 80 MPH wind and a margin of safety of 1.5. A correlation of skin thickness t, with cross-sectional radius r, for section BB is shown in Table II.

TABLE II V Skm Thickness Radius BB 111119 1 5). vcl El The above values were arrived at by assuming a force F, of 3,830 lbs. and a fiberglass working stress of X 10 psi. Although this working stress was assumed, other material may be used having working stresses of -150 X 10 psi. The reduction of skin thickness of the basic cross-section is directly related to an increase in working stress. The smaller thickness, larger radius structure is preferred for vehicle impact conditions.

In another embodiment of the invention the support structure was constructed using different variations in different segments of the support. The vertical component 22 used the constant skin thickness variation while the horizontal component 25 used the constant coplanar radius variation. The constant skin thickness vertical component provides for a ten percent increase in the major axis b, at section AA instead of a 20 percent increase in skin thickness t, at the same section. The thinner skin will also yield more easily when impacted by a vehicle. At the same cross-section'A-A the reduction in the minor elliptical axis a,, was only ten percent (see table I).

One reason for using a constant coplanar radius for the horizontal component was that a larger crosssection was attained at section D-D where the support mated with the sign. Also, for most of the horizontal component the minor axis a, is relatively uniform (see table I). With the major axis constant, a relatively uni- ELLIPTICAL C ROSS-SECTION VARIANCES Constant Skin Thickness Constant Co Ianar Radius axis 2 axis E skin form elliptical cross-section resulted. This fascilitated fabrication without a significant weight penalty.

In still another embodiment of the invention, the horizontal segment 26 used a constant skin thickness while the transitional segment 24 uses step laminations to A VERT P ORT.

Referring to FIG. 5, there is shown the vertical hingeline support 40 and associated dimensional parameters. The configuration of the support between sections E-E and FF is based upon the initially chosen dimensions of section GG which is in a horizontal plane with force F. The vertical hingeline support is similar to the vertical component of the horizontal hingeline support in that all horizontal cross-sections of the support are elliptical. For optimum strength, however, the reference section G-G is circular and all other sections between EE and FF are circular in a plane that passes through the force center of force F, at the midpoint of the sign. In FIG. 10 the vertical support is shown as having a constant coplanar radius. Note that in FIG. 5 the angle is measured from the vertical whereas it was previously measured from the horizontal in FIG. 4.

Although all sections between E-E and F-F are based upon section 6-6, the internal portion 32 of the support need not be based upon section GG. The entire portion 32, may for ease of fabricaton be cylindrical and circular in all horizontal planes so as to be compatible with the torque tube of the sign.

Assuming a vertical, straight support center line, the torque load T,,, for any section X-X is a function of the angle 0 to the particular section:

b, =r,=r,, mand For the case where the skin thickness, 1, varies and the coplanar radius (r,) remains constant, then the equations for a b and t for any section X-X are:

b, r p r,, and

. (28) 1s 2, 1,, E? m The distance y shown in FIG. varies with the position of section X-X and thus 0 is a function of y.

Referring to FIGS. 10A, 10B and 10C there are 5 axis a,, which is a smaller one than h The skin thickness at section X-X is larger than that at section GG. The side views of FIG. 108 shows the constant coplanar radius whereas the front view of FIG. 10A shows the tapered a dimension. Equation (27) indi- 30 cates that a, becomes smaller as 6 decreases, while equations (28) shows the constant r, relationship. Equation 29 shows that 2, increases with increases in the angle 0.

EXAMPLE VERTICAL SUPPORT Referring to FIG. 5 and Table 111 below, variations in a,, b, and t, are shown, calculated for varying skin thickness 2, and varying coplanar radius b, respectively. The value shown are non-dimensional and relate to sec- TABLE I11 ELLIPTICAL CROSS-SECTION VARIANCES Constant Skin Thickness Constant Co lanar Radius Station axis :1 axis 5 skin axis a axis b skin Section GG s F-F 0 2 4 6 s 10 E-E 12 T T,, sec 0, and

r, r, V sec 0 As previously stated, the change in torque with changes in torque arm between sections E-E and F -F can be compensated for by either varying the skin thickness 1, of the support or by varying the coplanar radius r,, of it. If the skin thickness remains constant then the equations for (1,, b, and I, as they relate to section (3-6 are:

Vsec F sin 0 a =r sin 0=r,,

r 1 r 1 1 r l r 1 1 Skin Thickness Radius GG 1 (inches) r (inches) -Continued Skin Thickness Radius G-G t (inches) r (inches) The above values were arrived at by assuming a force F, of 2,850 lbs. and a fiberglass working stress of 60 X 10 psi. The variations in skin thickness are inversely proportional to the radius at section G-G.

In another embodiment of the invention similar to that shown in FIG. 10 the top half of support 40 was constructed with a constant coplanar radius while the bottom half was constructed with a constant skin thickness. With such an arrangement the constant skin thickness on the bottom is provided for impact situations.

From the foregoing analysis of the concepts for the present invention and from the different illustrative embodiments shown, it should be apparent to one skilled in the art that various modifications of and departures from the concepts shown may be made, all of which are contemplated as falling within the spirit and scope of the present invention.

What is claimed is:

1. A sign structure comprising;

a sign having within its outer edges a force center line which is directed substantially perpendicularly to the face of said sign,

a support member having one end maintained stationary and including means for attaching the other end to said sign,

said support member including a substantially vertical section that is formed having a circular cross section in all planes that pass through the force center line of said sign and respective points along the length of said section,

said sign having an air foil shape and including means for receiving said attaching means of said support member,

said means for receiving being disposed off-center of said sign and spaced from said force center line.

2. A sign structure as defined in claim 1 comprising means for restraining said sign in a normal, readable position when normal forces are applied to said sign and for releasing said sign from said restrained position when said forces exceed a predetermined value, said sign including a fixed sleeve having a portion of said support structure contained therein.

3. A sign structure as defined in claim 1 wherein said restraining means includes a securing member located at one side of said sign and including means for at least temporarily engaging said sign.

4. A sign structure as defined in claim 3 wherein said securing member includes a cylindrical collar attached to said sign and having a hole therethrough, said supporting means includes a hole aligned with said hole in said collar, and a shear pin adapted to fit through said holes.

5. A sign support as defined in claim 1 wherein said support member includes a relatively thin outer jacket and a relatively light weight inner core material.

6. A sign support as defined in claim 5 wherein the thickness of said outer jacket remains constant-and the radius of said circular cross-section varies as a function of, the distance between said force center line and respective portions along said support member.

7. A sign support as defined in claim 5 wherein the circular cross-section remains constant and the thickness of said outer jacket varies as a function of the distance between said force center line and respective portions along said support member.

8. A sign structure as set forth in claim 7 wherein the radius of each of said circular cross sections is determined by the formula.

where r, radius in any of said cross sections r,, radius of said one circular cross section which lies in a plane horizontal with respect to gravity and through the force center F,

6 the angle from the force center F defined by the plane containing said one circular cross section defined by r,, and the plane containing the cross section defined in r,.

9. A sign structure as set forth in claim 7 wherein the skin thickness of each of said circular cross-sections is determined by the formula: 2, =1, sec 0 where t, skin thickness in any of said cross sections,

2,, skin thickness of said one circular cross-section which lies in a horizontal plane with respect to gravity, and through force center F,

6 angle from the force center F defined by the plane containing said one circular cross-section defined by r,, and the plane containing cross section defined by r,,.

10. A structure of claim 1 wherein said substantially vertical section has a progressively larger crosssectional area from the top to the bottom thereof.

11. A sign structure including a sign defining within its outer edges a force center line (F) which is directed substantially perpendicularly to the face of said sign, a support for said sign including horizontal and vertical members with said horizontal member having one end connected to said sign and the other to said vertical member, said vertical member having a circular cross section in all planes intersecting the force center and respective points along the vertical member for all angles of said plane that intersect said vertical member, said sign having an air foil shape and including means for receiving said attaching means of said support member, said means for receiving being disposed offcenter of said sign and spaced from said force center line.

12. A sign structure as set forth in claim 11 wherein all planes passing through said vertical support horizontal to gravity define on said bearing support an elliptical shape except for those also passing through said force center line F.

13. A sign structure as set forth in claim 12 wherein all of said planes passing through said force center line F define circular cross sections on said vertical support.

14. A sign structure including a sign defining within its outer edges a force center line (F) which is directed substantially perpendicularly to the face of said sign, a support for said sign including a vertical member having one end connected to said sign, said vertical member having a circular cross section in all planes intersecting the force center line (F) and respective points along said vertical member for all angles of said plane intersecting said vertical member, said sign having an air foil shape and including means for receiving said attaching means of said support member, said means for receiving being disposed off-center of said sign and spaced from said force center line.

15. A sign structure as set forth in claim 14 wherein all horizontal planes passing through said vertical support define an elliptical cross-sectional shape.

16. A sign structure as set forth in claim 14 wherein all of said planes passing through said force center line F define circular cross-sections on said vertical support.

17. A sign structure as set forth in claim 14 wherein the radius of each of said circular cross-sections is determined by the formula r, r sec where r, radius of any of said cross-sections,

r, radius of said one circular cross-section which lies in a plane horizontal with respect to gravity and through force center F, and

0 the angle from the force center F defined by a vertical plane and the plane containing the crosssection defined by r,.

18. A sign structure as set forth in claim 14 wherein the skin thickness of said circular cross-section is determined by the formula t t sec 0 where t skin thickness of said cross-sections,

t skin thickness of said one circular crosssection which lies in a plane horizontal with respect to gravity and through force center F, and

0 the angle from the force center F defined by a vertical plane and the plane containing the crosssection defined by r,. i

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,828,455 Dated August 13, 1974 Ralph L. Bentley Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet the illustrative figure should appear as shown on the attached sheet.,

Signed and sealed this 3rd day of June 1975.

(SEAL) Attest a C. MARSHALL DANN RUTH c. MASON Commissioner of Patents Attesting Officer and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 1. Patent No. ,455 Dated August 132, 1974 lgventofls) Ralph L. Bentley Page 2 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: 

1. A sign structure comprising; a sign having within its outer edges a force center line which is directed substantially perpendicularly to the face of said sign, a support member having one end maintained stationary and including means for attaching the other end to said sign, said support member including a substantially vertical section that is formed having a circular cross section in all planes that pass through the force center line of said sign and respective points along the length of said section, said sign having an air foil shape and including means for receiving said attaching means of said support member, said means for receiving being disposed off-center of said sign and spaced from said force center line.
 2. A sign structure as defined in claim 1 comprising means for restraining said sign in a normal, readable position when normal forces are applied to said sign and for releasing said sign from said restrained position when said forces exceed a predetermined value, said sign including a fixed sleeve having a portion of said support structure contained therein.
 3. A sign structure as defined in claim 1 wherein said restraining means includes a securing member located at one side of said sign and including means for at least temporarily engaging said sign.
 4. A sign structure as defined in claim 3 wherein said securing member includes a cylindrical collar attached to said sign and having a hole therethrough, said supporting means includes a hole aligned with said hole in said collar, and a shear pin adapted to fit through said holes.
 5. A sign support as defined in claim 1 wherein said support member includes a relatively thin outer jacket and a relatively light weight inner core material.
 6. A sign support as defined in claim 5 wherein the thickness of said outer jacket remains constant and the radius of said circular cross-section varies as a function of the distance between said force center line and respective portions along said support member.
 7. A sign support as defined in claim 5 wherein the circular cross-section remains constant and the thickness of said outer jacket varies as a function of the distance between said force center line and respective portions along said support member.
 8. A sign structure as set forth in claim 7 wherein the radius of each of said circular cross sections is determined by the formula. rx rb sec theta where rx radius in any of said cross sections rb radius of said one circular cross section which lies in a plane horizontal with respect to gravity and through the force center F, theta the angle from the force center F defined by the plane containing said one circular cross section defined by rb and the plane containing the cross section defined in rx.
 9. A sign structure as set forth in claim 7 wherein the skin thickness of each of said circular cross-sections is determined by the formula: tx tb sec theta where tx skin thickness in any of said cross sections, tb skin thickness of said one circular cross-section which lies in a horizontal plane with respect to gravity, and through force center F, theta angle from the force center F defined by the plane containing said one circular cross-section defined by rb and the plane containing cross section defined by rx.
 10. A structure of claim 1 wherein said substantially vertical section has a progressively larger cross-sectional area from the top to the bottom thereof.
 11. A sign structure including a sign defining within its outer edges a force center line (F) which is directed substantially perpendicularly to the face of said sign, a support for said sign including horizontal and vertical members wiTh said horizontal member having one end connected to said sign and the other to said vertical member, said vertical member having a circular cross section in all planes intersecting the force center and respective points along the vertical member for all angles of said plane that intersect said vertical member, said sign having an air foil shape and including means for receiving said attaching means of said support member, said means for receiving being disposed off-center of said sign and spaced from said force center line.
 12. A sign structure as set forth in claim 11 wherein all planes passing through said vertical support horizontal to gravity define on said bearing support an elliptical shape except for those also passing through said force center line F.
 13. A sign structure as set forth in claim 12 wherein all of said planes passing through said force center line F define circular cross sections on said vertical support.
 14. A sign structure including a sign defining within its outer edges a force center line (F) which is directed substantially perpendicularly to the face of said sign, a support for said sign including a vertical member having one end connected to said sign, said vertical member having a circular cross section in all planes intersecting the force center line (F) and respective points along said vertical member for all angles of said plane intersecting said vertical member, said sign having an air foil shape and including means for receiving said attaching means of said support member, said means for receiving being disposed off-center of said sign and spaced from said force center line.
 15. A sign structure as set forth in claim 14 wherein all horizontal planes passing through said vertical support define an elliptical cross-sectional shape.
 16. A sign structure as set forth in claim 14 wherein all of said planes passing through said force center line F define circular cross-sections on said vertical support.
 17. A sign structure as set forth in claim 14 wherein the radius of each of said circular cross-sections is determined by the formula rx rg Square Root sec theta where rx radius of any of said cross-sections, rg radius of said one circular cross-section which lies in a plane horizontal with respect to gravity and through force center F, and theta the angle from the force center F defined by a vertical plane and the plane containing the cross-section defined by rx.
 18. A sign structure as set forth in claim 14 wherein the skin thickness of said circular cross-section is determined by the formula tx tg sec theta where tx skin thickness of said cross-sections, tg skin thickness of said one circular crosssection which lies in a plane horizontal with respect to gravity and through force center F, and theta the angle from the force center F defined by a vertical plane and the plane containing the cross-section defined by rx. 